Press fit

[redvan22]

Hi,
I want to press a steel bearing racer into an aluminum handle. I tried leaving .002" and although I managed to get the bearing into the hole, it was a challenge and the rotation now is clicky, like indexed. I assume the bearing has been squished a bit. I tried looking up interference fit in my machinist handbook but it referenced a chart on a page that didn't exist in the book!

Is there a standard allowance for press fitting one object into another or is there a formula of some sort?

Mike

 

[Boswell]

I got this from some previous post but have not had an opportunity to test it.
.001 Inch of interference for every inch of diameter for a normal press fit

I also captured this formula for how to calculate thermal expansion that might help.

Formula for Thermal calculation	A=Rxbx(T-To)
A​	Change in Radius
R​	Radius at Room Temp
b​	Coefficient of Thermal Expansion
T​	Elevated Temperature
To​	Room Temperature

 

[Deleted member 69715]

I assume your bearing was washed and checked manually before being fitted and was found to be satisfactory. I think .001" is a bit too big for an interference fit; I would think .0002" to .0004" interference with an application of loctite would capture the race sufficiently. And since your present bearing is not turning smooth in the race it need to be replaced. Or thats what I would go for.

 

[T Bredehoft]

Surprise...other than that it was a good car.

Thanks for the fun.

 

[Deleted member 69715]

I was wondering when someone would "enjoy" that...

 

[Chewy]

I would run about 1/2 to 1 thousands. But the trick with aluminum is to heat it up to around 250 degrees and let the bearing drop into it. I pretty much heat or warm all the press fits that I can. Much easier to install.

 

[Ischgl99]

The fit for bearings depends on the use, for a rotating shaft, that would have the tighter fit and the housing would be a sliding fit. This is done so that it can be replaced fairly easy, and a point load will prevent the looser fit from causing the bearing to rotate in the housing. If you have tight fits on both components, you need to make sure to split the interference between each so that you do not take up all the internal clearance.

A typical fit will be k5 on a shaft and H7 on the housing. Small letter is for shafts, capital letter is for holes. What the actual measurements are will depend on the size. Unless your bearing is very large, 0.002” is way too much and you might have cracked a ring that is causing the clicking noise, or the hole is not round and it is binding as it rotates. Here is a table with fits for the holes,

ISO Hole Tolerance,ISO Hole Tolerances,Hole Tolerance,ISO 286-2 Hole Tolerances 3mm-400mm

ISO Hole Tolerance,ISO Hole Tolerances,Hole Tolerance,ISO Tolerance,ISO Hole Limits,Hole,Hole Limits,Engineering,Coban Engineering, Upper Limit,Lower Limit,

cobanengineering.com

 

[ChazzC]

P

Hi,
I want to press a steel bearing racer into an aluminum handle. I tried leaving .002" and although I managed to get the bearing into the hole, it was a challenge and the rotation now is clicky, like indexed.
Mike

0.002” is tight for a relatively small diameter, even for a shrink fit; however, just confirming that you used a socket or something similar to press just on the outer race?